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RE: Origins (was: Re: Sharovipteryx)



Absolutely nothing productive to add to Ralph's copious comments.
Basically, you could put me in as "ditto".  However, one thing I can add:

> From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of
> Ralph Chapman
>
> First of all - The mixing of the two hypotheses in questions, origins of
> taxa versus origins of flight, is logically awful - they are totally
> independent questions.

This has been totally missed by people on both sides of the debate(s), but
my favorite (and one of the most egregious examples) was at the SICB 1999
meeting.  Feduccia's paper (although not Feduccia himself - he was not able
to attend) described the two different models.  To illustrate the "trees
down model", which in their words was NOT supported by cladistics and
NECESSARILY non-dinosaurian, they used an illustration from Chattejee's The
Rise of Birds.  Which showed a "protoavian" in the trees, leaping on various
trajectories.

What they UTTERLY failed to point out was that:
a) Chatterjee's "protoavian" is explicitly labelled as a dromaeosaur in the
captions;
b) Chatterjee is a very strong advocate of the dinosaurian origin of birds;
c) Chatterjee's position is supported by his own numerical phylogenetic
analysis.

Since the majority of the people at the symposium were not paleontologists,
they had no way of knowing that they were being misled.  The figure used to
illustrate the "dichotomy" of the position was itself one that blasts that
dichotomy: a trees down, cladisitic, dinosaurian origin.

Let us hope the final print version does not have this mistake in a form
which might be citable in peer reviewed journals.

                Thomas R. Holtz, Jr.
                Vertebrate Paleontologist
Department of Geology           Director, Earth, Life & Time Program
University of Maryland          College Park Scholars
                College Park, MD  20742
http://www.geol.umd.edu/~tholtz/tholtz.htm
http://www.geol.umd.edu/~jmerck/eltsite
Phone:  301-405-4084    Email:  tholtz@geol.umd.edu
Fax (Geol):  301-314-9661       Fax (CPS-ELT): 301-314-7843